System
Identification Numbers, or SIDs, are 15-bit numeric identifiers used by
cellular systems to identify the home system of a wireless carrier and
by the cellular telephone to determine its roaming status. In the US,
cellular SID's had originally been assigned and recorded by the FCC. In
2003 the FCC decided to privatize the function of assigning and
recording cellular SIDs. Our lists are updated as changes are
discovered. Some entries are in the name of the legal office who
represents a wireless company. Note: Some of these
lists are large.

FCC's Administration of Cellular SID's:
The
administration of Cellular SID's was transferred to the private sector
on October 1, 2003. With the transfer of this responsibility, the SID
was removed from the cellular license. Cellular licensees seeking a new
SID assignment, an additional SID assignment, or licensees that have
ceased using an assigned SID, will be required to make their request /
notification through one of the recognized SID Administrators to
perform Cellular SID administration. Each organization will operate
under the general guidelines developed by the FCC and the cellular
industry.

Background:
The year 2000
biennial review of the Cellular Radiotelephone Service resulted in the
Commission eliminating System Identification Numbers from its rules.
This impacted cellular carriers in two ways:
1) Cellular SID
Administration would be transferred from the FCC to the private sector,
2) Once transferred, the SID would no longer be a term of a
cellular
license. In transitioning the SID administration function from the FCC
to the private sector, the Bureau kept the industry informed through
Public Notices and its website, drafted SID Administrator Guidelines
outlining the responsibilities of each administrator and requested
public comment, and signed a Memorandum of Understanding with each
recognized administrator.